Allylation of α-imino esters is one of useful synthesis reactions to provide various α-amino acid derivatives because products obtained by allylation of α-imino esters can be substituted with various functional groups. However, there are only a few cases of success of enantioselective allylation.
Lectka et al. and Jφrgensen et al. have both reported that a catalyst prepared from a combination of BINAP and a copper salt effectively functions in enantioselective allylation of α-imino ester whose nitrogen is protected by a p-toluenesulfonyl group, with the use of allylsilane and allyltin as allylating agents (yield 85%, 90% ee and yield 91%, 83% ee, respectively)
(Non-patent document 1, Non-patent document 2).
Meanwhile, in general, N-acylhydrazones are valuable compounds as imine equivalents easy to handle in organic synthesis. The present inventors have previously shown that for the purpose of developing organic synthesis reaction using water as reaction medium, a zinc fluoride-chiral diamine complex effectively promotes allylation reaction in which α-hydrazono ester is used instead of α-imino ester easily hydrolyzed in the presence of water, and have for the first time achieved enantioselective allylation of imine in a water-based solvent (yield 85%, 90% ee) (Non-patent document 3). In addition, the present inventors have found and reported that a complex obtained from a copper salt and chiral diamine effectively functions in allylation of α-imino ester (Non-patent document 4).    Non-patent document 1: T. Lectka et al., J. Org. Chem., 1999, vol. 64, pp. 2168-2169    Non-patent document 2: K. A. Jφrgensen et al., J. Org. Chem., 1999, vol. 64, pp. 4844-4849    Non-patent document 3: T. Hamada et al., Angew. Chem. Int. Ed., 2003, vol. 42, pp. 3927-3930    Non-patent document 4: Y. Nakamura et al., Org. Lett., 2003, vol. 5, 2481, unpublished results